Switching on SERS from SERS-inactive substrates through simple electrodeposition guided by defective molecular layers

Area of Science:

• Spectroscopy
• Surface Science
• Electrochemistry

Background:

• Raman scattering offers molecular identification but suffers from low intensity.
• Surface-enhanced Raman scattering (SERS) utilizes plasmonic surfaces for electromagnetic enhancement.
• Electrochemistry provides chemical enhancement via charge transfer (CT) resonance.

Purpose of the Study:

• To elucidate the enhancement mechanisms of unconventional electrochemical SERS (EC-SERS).
• To enable EC-SERS application on SERS-inactive flat metal surfaces.
• To expand practical access to SERS by simplifying substrate requirements.

Main Methods:

• High-resolution electron microscopy to analyze nanostructure formation.
• Tuning chemical conditions to clarify the role of CT resonance.
• Theoretical calculations to support experimental findings.

Main Results:

• A defective molecular monolayer is crucial for plasmonic nanostructure formation on flat surfaces.
• CT resonance plays a significant role in the enhancement mechanism.
• Successful EC-SERS application demonstrated on previously SERS-inactive flat metal surfaces.

Conclusions:

• Understanding EC-SERS mechanisms removes the need for sophisticated SERS substrates.
• This work expands SERS accessibility and provides a foundation for further enhancement.
• Insights pave the way for improvements in molecular, surface, theoretical, and electrochemical SERS.